def plan
    if params[:argument]
      unless params[:argument] =~ /^[1-4]$/
        flash[:notice] = 'Invalid plan number.'
        redirect_to :action => :index
        exit
        return
      end
    end

    @id = params[:id]

    # Pick the plan and then go to the
    # purchase page.
    if params[:argument]
      @firm = Firm.find(@id)
      @firm.plan = params[:argument].to_i

      if @firm.save
        redirect_to "/buy/first_account/#{@firm.id}"
      end
    end


  end